The effect of vitamin A supplementation on the growth of preschool children in the Sudan

OBJECTIVES

This study assessed the effect of vitamin A supplementation at 6-month intervals on child growth.

METHODS

Sudanese children (n = 28,740) 6 to 72 months of age were weighed and measured at baseline and at each of three follow-up visits.

RESULTS

Periodic vitamin A supplementation had no effect on the rate of weight or height gain in the total population or on the incidence of wasting, stunting, or wasting and stunting among children who were normally nourished at baseline.

CONCLUSIONS

Reducing poverty and improving access to adequate diets should remain the goals of programs designed to improve the nutritional status of malnourished populations.

Dietary vitamin A intake in relation to child growth

Severe deficits in ponderal and linear growth are problems of major public health significance among children in developing countries. We prospectively examined the association of dietary vitamin A intake with child growth among 28,740 Sudanese children ages 6-72 months. At baseline and at each 6-month visit, all subjects were weighed and measured. Dietary vitamin A intake during the prior 24 hours was assessed using recall of vitamin A-containing foods. Dietary vitamin A intake was associated with attained height and weight after controlling for age, sex, morbidity, and socioeconomic variables. Compared with children in the bottom quintile of intake, those in the top quintile were 11 mm taller [95% confidence interval (CI) = 8-13] and 237 gm heavier (95% CI = 153-320). Higher dietary vitamin A intake was also associated with reduced risk of stunting [relative risk (RR) for 5th vs 1st quintile = 0.7; 95% CI = 0.5-0.9] and wasting (RR = 0.7; 95% CI = 0.5-0.9). Adequate intake of foods containing vitamin A may improve child growth where vitamin A deficiency prevails, but this relation may not be due to vitamin A per se.

Maternal anthropometry and infant feeding practices in Israel in relation to growth in infancy: the North African Infant Feeding Study

Relations between maternal anthropometric status during pregnancy and infant feeding practices and growth from birth through the first 6 mo of life were examined in a cohort of 351 Israeli mother-infant pairs of North African descent. Maternal weight, height, and triceps skinfold thicknesses were determined at 6 and 9 mo of pregnancy, while infants' weights and lengths were measured at birth and at 1, 2, 3, and 6 mo of age with concurrent collection of age-specific maternal-reported infant feeding data. On the basis of multiple-linear-regression analysis that adjusted for potential covariates, mean maternal weight at the first prenatal visit and at 6 and 9 mo of pregnancy were positively associated with birth length (P for trend in all cases < 0.0001) and with linear growth between birth and 1, 3, and 6 mo of age. Maternal skinfold thickness at 9 mo of pregnancy and maternal height were also significantly associated with birth length. Moreover, maternal height, weight, and skinfold thickness at 6 and 9 mo of pregnancy were positively associated with mean birth weight. After adjustment for morbidity in the past month and other covariates, infants breast-fed exclusively had greater attained weight and weight gain in the first 3 mo compared with infants who were bottle-fed exclusively, breast-fed and bottle-fed, or solid-fed exclusively. These findings underscore the need for programs that improve the nutritional status of women before, during, and after pregnancy, and encourage exclusive breast-feeding of infants for at least the first 3 mo of life.

Risk factors of low dietary vitamin A intake among children in the Sudan

We examined the determinants of dietary vitamin A intake among Sudanese children, information which is important for designing effective interventions based on the dietary approach. Children under the age of two years were at greater risk of consuming a diet low in vitamin A compared with children who were five years or older. Compared with children from relatively affluent households, those from poorer households were about twice as likely to consume low levels of carotenoid or preformed vitamin A. Low vitamin A intake was also significantly associated with lack of running water, a latrine, radio, or television in the household, and inversely associated with maternal or paternal illiteracy and with cleanliness of the child subjectively assessed by the interviewer. As expected, breastfed children in the first two years of life were likely to consume lower levels of preformed vitamin A and carotenoid from food (excluding breast milk) compared with non-breastfed children. Low vitamin A intake was more prevalent in the dry months of the year. Efforts to increase accessibility to vitamin A containing food, combined with nutrition education campaigns and public health programmes directed at improving sanitation and reducing infection are necessary as part of the long-term solution to the problem of vitamin A deficiency.

A prospective study of malnutrition in relation to child mortality in the Sudan

We examined prospectively the relation between malnutrition and mortality among Sudanese children. A cohort of 28753 children between the ages of 6 mo and 6 y was examined every 6 mo for 18 mo. Two hundred thirty-two children died during 18 mo of follow-up (480624 child-months). Low weight-for-height was associated with an increased risk of mortality (P < 0.0001). Even children with Z scores between -1 and -2 were 50% more likely to die in the following 6 mo than were children with Z scores > -1 (multivariate relative mortality: 1.5; 95% CI: 1.1, 2.2). There was also an inverse relation between height-for-age and mortality (P < 0.0001). Among breast-fed children, the relative mortality associated with a Z score for weight-for-height of < -3 compared with > -2 was 7.3 (95% CI: 3.3, 15.9); among children not breast-fed, it was 26.0 (95% CI: 12.8, 53.0; P for interaction = 0.001). A strong and significant synergy was also found between infection and wasting or stunting as predictors of child mortality (P for interaction = 0.001 and 0.02. respectively). In developing countries, children who are below the customary cutoff point of -2 Z for weight-for-height may be at higher risk of death. Breast-feeding and reduction of morbidity should be advocated in programs designed to reduce malnutrition and mortality among children.

Dietary vitamin A intake and the incidence of diarrhea and respiratory infection among Sudanese children

The relationship of vitamin A deficiency and child survival has been documented in a number of studies but not in others, yet the relationship of vitamin A with child morbidity remains controversial. We prospectively examined the relationship of dietary vitamin A intake and the incidences of diarrhea and respiratory infection among 28,753 Sudanese children between the ages of 6 mo and 6 y. Total dietary vitamin A intake was strongly and inversely associated with the risk of diarrhea (multivariate risk in top relative to bottom quintile = 0.58, 95% confidence interval = 0.47-0.72); we also observed a strong inverse association with the risk of having cough and fever (0.60, 0.45-0.81). On the other hand, we noted a significantly positive association of dietary vitamin A intake and incidence of cough alone (1.69, 1.52-1.88), a sign that may be assocsated with a healthy respiratory epithelium. Vitamin A intake was also negatively associated with the risk of measles. These prospective data emphasize the importance of adequate dietary vitamin A intake to protect the health of children in developing countries.

Child nutrition and armed conflicts in Iraq

The object of the study was to assess the nutritional status of children 0-5 years, who were attending maternal and child health clinics in Basrah city, 6 months after the cessation of the Gulf War, and took the form of a cross-sectional study. The study population consisted of 723 children, the majority of whom were between 0 and 36 months of age, attending maternal and child health clinics (MCHC) in Basrah city for routine immunizations. Each MCHC was visited on a separate day and all children attending on that day were included in the study. A proportion (8 per cent) of the study population were wasted, most of them in the 12-24-month age category. Twenty-four per cent of the children were stunted. Stunting and low weight-for-age were significantly higher among children of low socio-economic households. Comparison of these data with an earlier nutritional survey in the area showed that the nutritional status of children in Basrah city has deteriorated as a result of successive armed conflicts. There is need to monitor the health and nutritional status of children, and take appropriate action in order to protect them.

Dietary vitamin A intake and the risk of mortality among children

Increased consumption of dietary vitamin A is advocated as a long-term solution to vitamin A deficiency. We prospectively examined the relationship of dietary vitamin A intake and child mortality among 28,753 Sudanese children aged 6 mo to 6 y, who participated in a trial of vitamin A supplementation. After 18 mo of follow-up, 232 children died. Total dietary vitamin A intake was strongly and inversely associated with risk of mortality. The age- and sex-adjusted relative risk (RR) of mortality for a comparison of children in extreme quintiles was 0.35 (95% CIs 0.21-0.60; P for trend over quintiles < 0.0001). Even after possible confounding by socioeconomic variables was adjusted for, vitamin A intake was significantly protective (multi-variate relative risk 0.53). Dietary vitamin A intake was especially protective among children who were wasted and stunted or who had diarrhea or cough. These prospective data support an important role of dietary vitamin A in reducing childhood mortality in developing countries.

Vitamin A supplementation and dietary vitamin A in relation to the risk of xerophthalmia

We examined the effect of 60-mg (200,000-IU) supplements of vitamin A administered every 6 mo on the incidence of xerophthalmia among preschool children who were free of eye symptoms and signs of vitamin A deficiency. We also prospectively studied the relationship of dietary vitamin A intake with the same endpoint. After 18 mo of follow-up, 400 children developed xerophthalmia during 80,104 child-periods of follow-up. Vitamin A supplementation only modestly reduced the risk of xerophthalmia (relative risk 0.88, 95% confidence interval 0.72-1.07, P = 0.19). On the other hand, total dietary vitamin A intake was strongly associated with reduced risk of xerophthalmia; the multivariate relative risk when children in extreme quintiles were compared was 0.38 (95% confidence interval 0.19-0.74; P for trend over quintiles = 0.002). These results emphasize the need for further data on factors that modify the bioavailability of large-dose vitamin A supplements. Increased consumption of inexpensive vegetables and fruits is highly likely to reduce significantly the risks of vitamin A deficiency, including nutritional blindness in developing countries.

Vitamin A supplementation and child mortality. A meta-analysis

OBJECTIVE

A two-part meta-analysis of studies examining the relationship of vitamin A supplementation and child mortality.

DATA SOURCES

We identified studies by searching the MEDLARS database from 1966 through 1992 and by scanning Current Contents and bibliographies of pertinent articles.

STUDY SELECTION

All 12 vitamin A controlled trials with data on mortality identified in the search were used in the analysis.

DATA EXTRACTION

Data were independently extracted by two investigators who also assessed the quality of each study using a previously described method.

DATA SYNTHESIS

We formally tested for heterogeneity across studies. We pooled studies using the Mantel-Haenszel and the DerSimonian and Laird methods and adjusted for the effect of cluster assignment of treatment groups in community-based studies. Vitamin A supplementation to hospitalized measles patients was highly protective against mortality (DerSimonian and Laird odds ratio, 0.39; 95% confidence interval, 0.22 to 0.66; P = .0004) (part 1 of the meta-analysis). Supplementation was also protective against overall mortality in community-based studies (DerSimonian and Laird odds ratio, 0.70; clustering-adjusted 95% confidence interval, 0.56 to 0.87; P = .001) (part 2 of the meta-analysis).

CONCLUSIONS

Vitamin A supplements are associated with a significant reduction in mortality when given periodically to children at the community level. Factors that affect the bioavailability of large doses of Vitamin A need to be studied further. Vitamin A supplements should be given to all measles patients in developing countries whether or not they have symptoms of vitamin A deficiency.

Vitamin A supplementation and child survival

Previous studies of the effect of 6-monthly vitamin A supplementation on child mortality have given conflicting results. In other trials, more frequent doses of vitamin A have significantly reduced mortality among children at risk of vitamin A deficiency. We have done a double-blind, placebo-controlled trial of vitamin A supplementation in the Sudan among 28,753 children aged 9-72 months at risk of vitamin A deficiency. Children were assigned to receive either 200,000 IU vitamin A and 40 IU vitamin E every 6 months (vitamin A group) or 40 IU vitamin E alone (placebo group). During the 18 months of follow-up, there were 120 deaths (8.4/1000) in the vitamin A group and 112 (7.9/1000) in the placebo group (relative risk 1.06, 95% confidence interval 0.82-1.37). Controlling for geographic site, round of observation, anthropometry, morbidity, dietary intake of vitamin A, sex, and all baseline differences between the two groups did not change the results. Children living in poor and unsanitary environments, younger children, and those sick, stunted, wasted, or consuming diets low in vitamin A were at a significantly higher risk of dying. The lack of an effect of large-dose vitamin A supplementation on mortality, despite a clear association between dietary vitamin A and mortality, underscores the need to identify factors that modify the efficacy of vitamin A supplements as a public-health measure. Reducing poverty, improvements in sanitation, and access to adequate diets should remain the main goals to improve child survival.